Sound indicating apparatus



Feb. 20,1940. w. P. PLACE ET AL SOUND INDICATING APPARATUS Filed Nov. 5, 1956 o Q i 0 (Dillard P. Place 7 S Evder'z'c'kCSml' THEIR ATII'ORNEY Patented F eb. 2Q, 1940 UNITED STATES PATENT OFFICE 2,191,203 SOUND INDICATING APPARATUS Willard P. Place, Penn Township, Allegheny County, and Frederick C. Smith, Wilklnsburg, Pa.

Application November 5, 1936, Serial No. 109,392 Claims. (Cl.1810.5)

q ybearings B2, carries a plurality of gears cor- 10 We will describe one form of apparatus emresponding in number to the gears .carried by bodying our invention, and will then point out shaft H2. In one position of shaft H2, gear El the novel features thereof in claims. will mesh with gear E4 of shaft H3, as shown in In the accompanying drawing, Fig. 1 is a dithe drawing; in a second position of shaft H2, agrammatic view showing one arrangement of gear E2 will mesh with gear E5; and in a third 15 electrical circuits and associated devices for use position of shaft H2, gear E3 will mesh with gear in apparatus embodying our invention. Fig. 2 E6 of shaft H3. On the left-hand end of shaft is a view, in side elevation, showing an arrange- H3, as shown in the drawing, a circular disc D is ment of gears and shafts through which a vcrtlmounted. cal disc D is rotated by a motor M, in apparatus Passing through disc D, are holes arranged in '20 embodying our invention 3 s an enlarged circles concentrically about the axis of disc D view, in front elevation, of a portion of disc a portion of which is shown in an enlarged view D show in 4 s B, View, s n front in Fig. 3. As here shown, there are twelve such elevation, of a control and indication panel A circles, corresponding to the seven tones and five for apparatus embodying our invention. semi-tones beginning with C and ending with B 25 Similar reference characters refer to similar in any given octave of the major musical scale. parts in each of the views. Grid glow tube GG is mounted back of the up- Re rr ng fi to the ces e wn per portion of disc D, and a control and indiare a m r ph n P; a ans rm r Tl havin cation panel A is mounted in front of disc D, a primary winding l and a secondary winding as shown in Fig. 2. 30 a transformer T2 having a P y Wi As shown in Fig. 4, a screen or sheet U of trans- 3 a d se o y windings 7 d 8; an lucent material, such for example as Celluloid, amplifier tube 0f the indirect heater typ covers a rectangular opening through panel A. having a grid a d fi n and a Particularly for the use of musicians, seven lines plate a grid. 8 tube G ha g a grid areruled across translucent sheet U, and the 5 l3, filament l4, and a plate l5 (some other suitl tters 0, d, e, f, g, a. and b, are placed adjacent able source of light may be used instead of grid the ends of these lines, as shown in the drawing, glow tube GG); an inductor L; a rectifier tube to designate the corresponding tones of a musi- 80; a synchronous motor M; a circuit closer S, cal octave. Switch S, previously referred to in 40 which may be of the snap switchtype, for conconnection with Fig. 1, is mounted on the lower 40 necting motor M and primary winding 3 of transleft-hand portion of panel A. A lever or knob former T2 with a source of alternating current K is mounted on the lower right-hand p n which may be of 60 cycle frequency, the terof pan l A. f r perat n th ar sh ft l v r F, minals of which are designated a: and 0; conshown in Fig. 2, through suitable linkage repredensers designated by the reference character n e y e dash e Switch own C with distinguishing numerals; resistors desso i s mounted o p n A between ignated by the reference character R. with disswitch 5 and level tinguishing numerals; a switch N for connect- In order to obtain an indication of a sound ing to various parts of resistor R9 for varying or musical note, a musician or other operator will 5 the grid bias of tube 21; and ground connections manipulate switch S on panel A to the closed Our invention relates to sound indicating apparatus, and particularly to such apparatus which is selectively responsive to the vibrational frequency of sound.

One feature of our invention is the provision of means for visually indicating to a musician the accuracy with which any given note is being played or sung, or for indicating sound for any other purpose according to its vibrational fredesignated by the reference character n with distinguishing numerals.

In Fig; 2, a gear EM is shown mounted on the shaft of motor M for driving shaft HI through gear EH. Shaft III is supported on bearings Bl. A hollow shaft H2 is arranged to slide along shaft HI, and may be rotated with shaft HI by splines I! set in shaft HI. Shaft H2 carries a plurality of gears, three of which, El, E2 and E3, are shown here. For use of musicians, 5 shaft H2 may have a gear E for each octave of the musical scale. A gear shift lever F is provided for setting shaft H2 in various given positions along shaft HI. A shaft H3, supported on position; willset switch N according to the loudness of the sound; and will set lever K according to the octave in which the sound is located. The

closing of switch S will start operation of motor M, and will energize primary winding 3 of trans- I former T2. Rectifier tube 80 is then energized by transformer T2, and supplies high voltage current through a filter J made up of inductor L and condensers C6 and Cl. Microphone P is energized by current from filter J passing through resistor R1.

Microphone P, in response to a given sound or musical note, produces variations in its energizing current corresponding to the vibrational frequency of such given sound or musical note. The current thus varied by microphone P energizes primary-winding l of transformer TI and secondary winding 2 of this transformer then applies a voltage correspondingly varied to grid 9 of amplifier tube 21. Grid bias is applied to grid 9, through switch N, by a voltage divider resistor R9. Plate voltage is applied to tube 21 from filter J through resistors R6 and R2 arranged in a voltage divider circuit.

Amplified higher voltage, varied according to the variations of the microphone current, is ap:- plied to grid l3 of grid glow tube GG through the resistance coupling means comprising resistor RI, condenser C4 and resistor R3. The input circuit for tube GG includes ground n3, resistors R2 and RI, condenser C4, resistor R4, grid I3, filament ll, secondary winding I of transformer T2, and

ground n1. Grid bias is applied to grid l3 by -voltage divider R8. Plate voltage is supplied to plate l5 of grid glow tube GG through resistor R5.

Each time the voltage which is applied to grid I3 increases in accordance with a change in the microphone current, tube GG triggers off or breaks down'in its plate circuit which includes ground n6, resistors R8 and R9 in multiple, secondary winding 4-5 of transformer T2, rectifier tube 80, filter J, resistor R5, plate l5 and filament H of tube GG, secondary winding 1 of transformer T2, and ground 121. During the intervals between the times at which tube GG breaks down, condenser C5 is being charged up, by a circuit which is the same as the plate circuit traced for tube GG from ground n6 as far as resistor R5, and then including condenser-C5 and ground 124 and when tube GG breaks down, condenser C5 discharges abruptly through tube GG, causing tube GG to emit a brilliant flash of light. In this way, tube GG gives one flash oflight for each cycle of the variations in the microphone current. Since the variations in the microphone current are at the vibrational frequency of the sound or note by which they are produced, the flashes of light emitted by tube GG are also at the vibrational frequency of the sound or note to which microphone P responds.

The flashes of light from tube GG shine through the upper portion of the circles of holes in disc D and onto screen U of panel A. When the flashes of light are at the same frequency as the holes in one of the circles pass in front of tube GG, there will be a stationary spot of light on screen U at a point corresponding to the note which is being played or'sung.

If, for example, the apparatus were so designed that, for the middle octave of the major musical scale, disc D were rotated at a speed of 60 revolutions per minute, the circle on disc D corresponding to note A would contain 440 holes, since the vibrational frequency of note A is 440 cycles per second. The circles for other notes would have numbers of holes corresponding to the vibrational frequencies of these notes. If, now, note A were sounded accurately, a stationary spot of light would appear on the 1ine marked a on screen U. Streaks of light would at the same time appear on the lines corresponding to the other six notes, and between some of these lines corresponding to the five semi-tones.

If, on the other hand, note A were inaccurately sounded, so that there were 441 instead of 440- flashes of light per second, the flashes of light would get farther and farther ahead of the holes in the circle for note A, and hence, if the disc were turning in the clockwise direction, the spot of light, and other similar spots in succession, would move to the left. If the flashes of light were slightly less than 440 per second, the spots of light would move to the right.

It follows that when there is a stationary spot of light for any given note, the musician will known that the note is being acurately sounded.

and if the spot moves to either the left or the right, the proper correction can be made in rendition to cause the note to be correct, as will be indicated by the spot becoming stationary. If the note is inaccurately sounded, the rapidity with which the spots of light corresponding to this note move either to the left or to the right indicates to the musician how badly the note is out of tune.

Although we have herein shown and described only one form of sound indicating apparatus embodying our invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of our invention.

Having thus described our invention, what we claim is:

1. In combination, apparatus responsive to sound for translating sound vibrations into electric current variations having corresponding frequencies, a grid glow tube, means connected to said sound responsive apparatus and to said grid glow tube and responsive to said electric current variations for applying amplified higher voltage correspondingly varied at these frequencies to the grid of said grid glow tube, .a plate circuit including a source of current and the plate of said grid glow tube in which said 'grid glow tube triggers off" or breaks down each time the voltage which is applied to said grid'increases in accordance with said electric current variations, and a condenser connectedwith said plate circuit and becoming charged during the intervals between the times at which said grid glow tube breaks down and becoming discharged abruptly through said grid glow tube each time said grid glow tube breaks down and thereby causing said grid glow tube to emit brilliant flashes of light.

2. In combination, apparatus responsive to sound for translating sound vibrations into electric current variations having corresponding frequencies, a gaseous discharge tube having a plate and a grid, means connected to said sound responsive apparatus and to said gaseous discharge tube and responsive to said electric current variations for applying amplified higher voltage correspondingly varied at these frequencies to the grid of said gaseous discharge tube, a plate circuit including a source of current and the plate of said gaseous discharge tube in which said gaseous discharge tube triggers off or breaks down each time the voltage which is applied to said grid increases in accordance with said electric current variations, and auxiliary apparatus controlled by and connected with said plate circuit for applying an additional pulse of current to said gaseous discharge tube each time said gaseous dis-' charge tube breaks down and thereby causing said variations having corresponding frequencies, a gaseous discharge tube having a plate and a grid,

means connected to said sound responsive means and to said gaseous discharge tube and controlled by said electric current variations for applying amplified higher voltage correspondingly varied at the same frequencies to the grid of said gaseous discharge tube, means connected to said gaseous discharge tube for applying grid bias to the grid of said gaseous discharge tube, a plate circuit including a source of current and the plate of said gaseous discharge tube in which said gaseous discharge-tube triggers oi! or breaks down each time the voltage which is applied to said grid increases in accordance with said electric current variations, and a condenser connected with said plate circuit and becoming charged during the intervals between the times at which said gaseous discharge tube breaks down and becoming discharged abruptly through said gaseous discharge tube each time said gaseous discharge tube breaks down and thereby causing said gaseous discharge tube to emit sharp flashes of light.

4. In combination, apparatus responsive to given musical tones for translating a series vibrations of each of said musical tones into cycles ofelectric current variations having frequencies corresponding to the frequencies of the vibrations of said musical tones, a device capable of emitting light, means connected to said tone responsive apparatus and to said device and responsive to said electric current variations for applying correspondingly varying current to said device, and

., auxiliary apparatus connected to said device and controlled by said electric current variations for applying an additional pulse of current to said device for each of said cycles of electric current variations for controlling said device to emit a sharp flash of light for each of said pulses of current.

5. In combination, apparatus responsive to given musical tones for translating a series of vi- "brations of each of said musical tones into cycles of electric current variations having frequencies corresponding to the frequencies of the vibrations 01 said musical tones, a device capable of emitting light, means connected to said tone responsive apparatus and to said device and responsive to said electric current variations for applying correspondingly varying current to: said device, and means connected to said device and controlled by said electric current variations for applying additional current to said device during a portion of each of said cycles of electric current variations for controlling said device to emit a flash of light during such portion oi. each of said cycles of electric current variations.

WILLARD P. PLACE. FREDERICK C 

